Analysis of Temporal Variation of Soil Salinity during the Growing Season in a Flooded Rice Field of Thessaloniki Plain-Greece

The effects of regional water management practices (WMPs) on the soil salinity of a representative rice field under Mediterranean conditions (Thessaloniki plain, Greece) were investigated. The temporal variation of soil salinity parameters in the soil solution and in the exchangeable phase was monitored at and below the root zone (15-20 and 35-40 cm) during the growing season. The comparative analysis (ANOVA for p = 0.05) of the measurements before and after the growing season showed that: (a) for the soil solution of the 15-20 cm layer, Ca2+, Mg2+, K+, HCO3- and EC were significantly reduced, Na+ remained constant and Cl- increased, while in the 35-40 cm layer no significant differences were detected to all parameters except for Cl- which was increased; (b) for the exchangeable cations Ca2+, Mg2+ and K+ no significant differences were found, while exchangeable Na+ and ESP were significantly increased in both soil layers during the short period of soil drying before harvest. The final values of Na+ and ESP were quite low to indicate soil degradation hazard. Overall the results showed adequate performance of WMPs to preserve a good soil salinity status but with the cost of high water consumption, exceeding 2000 mm.